Patent GB-775753-A (GB)
Title: Improved steerable trailer
IPC: B62D13/04
Filed: 1952-01-22
Abstract: 775,753. Steering trailers. WHEATLEY, C. H. P. April 17, 1953 [Jan. 22, 1952], No. 1776/52. Class 79(5). [Also in Group XXXIV] A trailer has wheels steerably deflected by the change in relative inclination of the trailer and a tractor to which it is adapted to be attached, the steering is adjustable for operation in both directions of running, and the extent of the wheel deflection is substantially equal but in the opposite direction in opposite directions of running. As shown in Fig. 1, the invention is applied to a trailer 2 having wheels 3 rotatable about the axis of a pin 5. Rotation of the pin 5 is caused by means of an arm 7 connected by a link 6 to a lever 14 which may be pivoted at 16 or 17 to the trailer frame 1, the pivoting at 16 or 17 depending on whether the trailer is preceding or following the tractor. The lever 14 is connected by a link 19 to an L-shaped lever 20 pivoted at 9 to the trailer frame 1, the other arm of the lever being slidably connected to a mounting 12 on the frame 11 of the tractor. The sliding connection with the mounting 12 is provided when overrunning of the trailer operates the latter's brakes. If required the link 19 may be pivoted directly to the member 13 of the tractor frame. In a modification, Fig. 3, the trailer wheels 3 are steerably deflected about axes 21 and are interconnected by arms 24 and a rod 22. One of the arms 24 has an extension 23 which is connected by the link 6 to a two-armed lever 26 pivoted at 27 to the trailer frame 1. Each arm of the lever 26 is connected by a two-part member to the L- shaped lever 20. The two parts of each member are adapted to be pinned together and one of the members is provided with a pinion on one of its parts engaging a rack on the other part and operated by a hand wheel to facilitate the pinning of the parts together. The arrangement is intended for one of the two-part members to be operative when the tractor and trailer are going in one direction and the other member when going in the other direction. The hand wheel may be employed to steer the trailer independently of the tractor. The pin may be connected to a disc having diametrical notches capable of engaging the pin housing whereby the pin can be held in its operative and inoperative positions, Fig. 5 (not shown). As an alternative to the rack, pinion and hand wheel arrangement for independent trailer steering the lever 20, Fig. 6, may have its mounting 12 rotatable about a vertical axis by having an arm 43 which is provided with a nut 44 engaging a threaded shaft 45. The shaft 45 can be rotated by a hand wheel 46 at the rear of the tractor or by a hand wheel 47 in the driving cabin. As shown in Fig. 7 the invention is applied to a four-wheeled trailer, the axle carrying the front wheels 3 being rotatable about a vertical axis and the rear wheels 3a being deflectable about axes 21. The L-shaped lever 20 is connected to a link 50 carrying a roller 51 engaging a channel 53 which is pivoted to a draw bar 48 which may carry a loadcarrying platform and is hinged to the lever 20 and to the trailer frame. The channel 53 can be arranged either longitudinally or transversely dependent on the direction of movement of the tractor and trailer. The link 50 is connected to the swivelling portion of the axle carrying the wheels 3, to which portion is also connected a link 50a. The link 50a carries a roller 51a engaging a channel 53a pivoted similarly to the channel 53 but intended to be at right angles to the same. The link 50a is connected by a link 6a to the extension 23 of one of the steering arms 24 associated with the rear wheels 3a. It is stated that a trailer may be provided both at the front and at the rear of the tractor and the invention may even be applied to a train of vehicles, the tractor taking any desired position in the train. It is also stated that the invention is applicable to a vehicle having an articulated section or in which pairs of wheels are mounted on separate frames hinged to the vehicle frame. The invention is not limited to wheeled vehicles but may be applicable to vehicles having skids, endless tracks or floats.